1. Field of the Invention
The present invention generally relates to medical devices for the administration of medicines, drugs, and other therapeutic materials and more specifically to a syringe having an integrated cannula and components related thereto.
2. Description of Related Art
In the early stages of syringe use, medical professionals relied on reusable glass hypodermic syringes and needles which were boiled for sterility after each use. Although accomplishing the goal of delivering medication into the human body in a sterile manner, these early glass syringes were relatively cumbersome and crude in design. As early as the 1950's, the idea for a disposable syringe came to pass. With the development of new materials, the plastic disposable syringe was a great advancement providing increased disease prevention over prior designs.
Today, the most common plastic disposable syringe comprises a syringe barrel having an internal chamber and a plunger rod disposed in the chamber which can either draw fluid into the chamber, or expel fluid from the chamber. Typically, the tip of the syringe includes a hollow tubular projection or nozzle encompassed by a threaded outer circular structure, sometimes referred to as a “Luer lock” or a “Luer slip,” that is adapted to engage with a needle hub or other device that has a hub (i.e. Luer fitting) configured to mate with the circular structure. For purposes of hypodermic injections, the needle hub typically has a hypodermic needle of varying length that is in fluid flow communication with the chamber of the syringe when joined to the barrel.
In a typical setting, more than one needle hub is required to carry out an injection operation. First, a draw-needle hub having a relatively large-bore steel needle must be attached to the syringe, which draw needle is then inserted into a medicine container. In some cases, the medicine container has a pre-slit rubber septum allowing for easier access. In any event, the plunger rod is pulled outward, drawing the medicine from the container, through the draw needle, and into the chamber. At that point, the technician must then remove the draw needle hub from the container, detach the hub from the syringe and set it aside, and then attach an injection-needle hub that has a relatively small-bore hypodermic needle back onto the syringe. Finally, the injection can be carried out. This multi-step procedure has several disadvantages. For one, the technician must remove and replace the draw-needle hub with the injection-needle hub which can compromise overall sterility of the procedure while also exposing the technician and patient to the risk of needle sticks from the draw-needle hub that is set aside. Additionally, confusion could occur between the two needle hubs, causing the technician to inadvertently inject the patient using the large-bore and presumably less sterile draw needle. The overall procedure is generally cumbersome in that it requires the technician to interact with several different components, i.e. syringe, draw hub, injection hub, medicine vile, etc. Finally, because the syringe and its various needle hubs are disposable, a standard injection procedure requiring at least two different needle hubs can become exceedingly expensive over time.
There have been numerous attempts to develop improved medical syringes; however, none adequately solve the shortcomings outlined above.
For example, U.S. Pat. No. 5,158,554 to Jepson et al. describes a syringe having a cannula configured to be received in a pre-slit injection site such as an IV (intravenous) entry path. Included is a housing having a pre-slit septum adapted to receive a blunt cannula having a locking member. The locking member is adapted to latch to the injection site forming a mechanically coupled unit with the housing. The cannula is designed to engage a male-threaded Luer-lock of the syringe such that the cannula is removable and replaceable with an injection needle hub or the like.
U.S. Pat. No. 6,165,153 to Kashmer describes a single-use syringe assembly including an elongated syringe barrel receiving a plunger rod having a plunger tip. The syringe barrel has a nozzle at its closed end formed to receive the plunger tip. The distal end of the nozzle contains an annular inward biased ring adapted to mate with a locking detent on the plunger tip. Upon usage, when the plunger reaches its full range of motion inward, the locking detent is irreversibly matted with the nozzle inwardly biased ring, thereby preventing the reuse of the syringe assembly. The distal end of the syringe includes a Luer-type threaded needle mount that is adapted to receive a variety of draw and injection needle assemblies or other Luer-type hubs.
U.S. Pat. No. 7,351,228 to Keane et al. describes an arterial blood collection syringe having a self-sealing filter provided at the front end of the plunger rod. Vents are spaced radically about the front end of the plunger. The plunger is received in a syringe barrel which barrel has a fitting at its distal end adapted to receive a variety of needle hubs including a draw-needle hub and a hypodermic injection-needle hub.
U.S. Pat. No. 7,534,233 to Schiller et al. describes an IV flush syringe assembly having a barrel with an inside chamber for retaining fluid, an open proximal end and a distal end including a distal wall with an elongate tip extending distally therefrom having a passageway in fluid communication with the chamber. A plunger is disposed in the chamber. An anti-reflux structure is disposed in the barrel for controlling plunger-stopper deflection when the fluid has been delivered from the chamber wherein the stopper is on contact with structure on the distal wall of the chamber. A needle assembly is configured to removably attach to the distal end of the barrel wherein the assembly includes hub attached to a needle or blunt cannula.
Becton, Dickinson and Company markets a product under its BD Medical brand called the “BD Twinpak” which includes a syringe having a standard Luer-lock type fitting adapted to releasably receive a specialized hub having a “blunt plastic cannula.” The removable plastic cannula is limited to split-septum access in connection with BD's IV receptacles. The “Twinpak” also includes a “red hub filling device” which includes a draw-needle which is needed in order to fill the syringe prior to fitting it with the blunt plastic cannula. Accordingly, the technician must first use the red hub filling device to draw medicine into the syringe and then remove and replace it with the blunt plastic cannula for subsequent IV access.
Despite some improvements, each of the devices described above still relies on a separate draw-needle hub in order to fill the chamber of the syringe, and the technician must still swap out the draw-needle hub with an injection hub (whether a needle-based or needleless, in the case of the BD Twinpak) before an hypodermic injection or other medicine delivery (e.g. IV or catheter port) procedure can be completed. Thus, these improved devices still have all of the disadvantages associated with traditional disposable syringes outlined above. With that in mind, there is a definitive need for a syringe assembly and system that completely eliminates the need for large bore draw-needles and hubs while also eliminating the multi-step injection procedure associated therewith.
It is, therefore, to the effective resolution of the aforementioned problems and shortcomings of the prior art that the present invention is directed. However, in view of the syringe assemblies in existence at the time of the present invention, it was not obvious to those persons of ordinary skill in the pertinent art as to how the identified needs could be fulfilled in an advantageous manner.